Evaluation of prolidase activity and oxidative stress in patients with oral lichen planus and oral lichenoid contact reactions.

OBJECTIVE: The aim of this study was to evaluate prolidase activity and oxidative stress in patients with oral lichen planus (OLP) and oral lichenoid contact reactions (OLCR) using serum and salivary samples and to compare these biomarkers with each other as well as with a group of healthy subjects in order to be able to opine their role in the estimation of OLP and OLCR. PATIENTS AND METHODS: Eighteen recently diagnosed patients with OLP, 32 patients with OLCR and 18 healthy controls with matched periodontal status were recruited to the study. Prolidase activity, lipid peroxidation product malondialdehyde (MDA), sialic acid (SA), and advanced oxidation protein products (AOPPs) levels in both serum and saliva were determined. Additionally, salivary flow rate and its buffering capacity were estimated. Statistical analyses were performed using the chi-square test, t-test, Mann-Whitney U-test, and Spearman's rho correlation coefficient. RESULTS: No statistically significant differences were observed between the study groups and the control group regarding to the basic characteristics and the periodontal status (P > 0.05). There were no statistically significant differences between OLP and OLCR groups regarding to the distribution of lesions' type, severity, and location (P > 0.05). No significant differences were found between the two study groups with regard to Prolidase activity, MDA, SA, and AOPPs (P ˃ 0.05), whereas statistically significant differences were found between the two study groups and the control group with regard to all evaluated parameters except of serum prolidase (P ˂ 0.01). Moderate correlation was found between salivary MDA and the OLP/OLCR lesion severity, whereas a weak correlation was observed between serum SA and the OLP/OLCR lesion severity (P ˂ 0.05). CONCLUSIONS: The findings of this study suggest an increased prolidase activity and oxidative stress and imbalance in the antioxidant defense system in biological fluids of patients with OLP and OLCR when compared with the healthy subjects. Both OLP and OLCR patients revealed almost similar prolidase activity and oxidative stress levels although these two conditions have different etiopathogenesis.

[Plasma and salivary markers of oxidative and carbonyl stress in patients with acute intermittent porphyria]. / Markery oxidacného a karbonylového stresu v plazme a slinách u chorých s akútnou intermitentnou porfýriou.

BACKGROUND: Acute intermittent porphyria (AIP) is an autosomal inherited disease caused by deficiency of the third enzyme in the heme biosynthetic pathway, porphobilinogen deaminase. The clinical course of the disease is characterized by acute attacks, most often with abdominal pain.The aim of our study was to investigate selected markers of oxidative and carbonyl stress in plasma and saliva in patients with AIP and to find out whether saliva could be used for monitoring the disease progression. Saliva is an attractive biological fluid for determination of biochemical markers in various pathological conditions. The advantage is that saliva can be collected non-invasively, and the examination needs only a small volume of saliva. METHODS: Blood and total non-stimulated saliva were collected from 16 patients with AIP in remission, and from 20 healthy individuals. Markers of oxidative and carbonyl stress - advanced glycation end products (AGEs), and thiobarbituric acid reacting substances (TBARS) were determined by spectrofluorometric methods, advanced oxidation protein products (AOPPs), total antioxidant capacity (TAC) and ferric reducing ability of plasma/saliva (FRAP/FRAS) were investigated by spectrophotometric methods in the above mentioned groups. RESULTS: Advanced glycation end products and thiobarbituric acid reacting substances in plasma and saliva were significantly higher in patients with AIP in comparison to the control group (p < 0.001) and (p < 0.05). Advanced oxidation protein products in AIP if compared to the control group did not show statistical significance (p > 0.05), but the levels in the saliva were significantly lower (p < 0.001). The concentrations of markers of antioxidant status of plasma and saliva were significantly lower in AIP if compared to the control group (p < 0.001). CONCLUSIONS: According to the best of our knowledge this is the first study to demonstrate increased concentrations of markers of oxidative and carbonyl stress and decreased antioxidant status of plasma and saliva in patients with AIP. Moreover, the study suggests that the saliva might be a promising fluid to study relevant biomarkers in a wide array of human biomedical conditions.Key words: acute intermittent porphyria - biomarkers - oxidative and carbonyl stress - plasma and saliva.

Salivary markers of oxidative stress in patients with obstructive sleep apnea treated with continuous positive airway pressure.

PURPOSE: Obstructive sleep apnea syndrome (OSAS) is characterized by elevated oxidative stress. Measurement of oxidative stress in saliva seems to be promising in long-term treatment monitoring of OSAS patients. In this study, our aim was to investigate whether short-term continuous positive airway pressure (CPAP) treatment would influence oxidative stress in saliva. METHODS: Patients with diagnosed OSAS (16 women, 28 men) underwent polysomnography during the first night and CPAP treatment during the second night. Saliva samples were taken in the evening and morning on both days. Markers of oxidative stress and antioxidant status were analyzed in saliva. RESULTS: Evening concentrations of the salivary thiobarbituric acid reacting substances (p < 0.001), advanced glycation end-products (p < 0.001), and advanced oxidation protein products (p < 0.01) were significantly lower than morning values during the diagnostic night. However, salivary concentrations of none of the oxidative stress markers were significantly influenced by the CPAP treatment. No changes in salivary antioxidant status after CPAP therapy were found. CONCLUSION: Salivary markers of oxidative stress and antioxidant status do not change significantly after one night treatment with CPAP. On the contrary, after 1 month with CPAP therapy, reduced markers of oxidative stress were reported. Therefore, the future studies should be focused on finding the optimal sampling frequency to clarify the potential of saliva for the monitoring of OSAS treatment.

Relation of middle molecules levels and oxidative stress to erythropoietin requirements in high-flux versus low-flux hemodialysis.

The objective of this study is to investigate the serum beta-2-microglobulin (B2MG) and advanced oxidation protein products (AOPP) as middle molecule uremic toxins and protein carbonyl (PCO) as oxidative stress marker in uremic patients undergoing high-flux versus low-flux hemodialysis (HD) and to correlate their levels to the erythropoietin requirements for those patients. Twenty patients on chronic low-flux HD were recruited in the study. At the start of the study, all patients underwent high-flux HD for eight weeks, followed by low-flux HD for two weeks as a washout period. The patients were then subjected to another eight weeks of low-flux HD. Blood samples were obtained at the beginning and at the end of the high-flux period and the low-flux period. The mean erythropoietin dose for patients using high-flux HD was significantly lower than that for low-flux HD (P = 0.0062). Post-high flux, the B2MG and PCO levels were significantly lower than the pre-high-flux levels (P = 0.026 and 0.0005, respectively), but no significant change was observed in AOPP (P = 0.68). Post-low flux, the B2MG, AOPP and PCO were significantly higher than the pre-low-flux levels (P = 0.0002, 0.021 and <0.0001, respectively). Post-low flux, the B2MG and PCO were significantly higher than the post-high-flux levels (P <0.0001), but no significant difference was observed in AOPP (P = 0.11). High-flux HD results in reduction of some of the middle molecule toxins and PCO levels better than low-flux HD, and is associated with a better response to erythropoietin.

The effects of supplemental melatonin administration on the healing of bone defects in streptozotocin-induced diabetic rats

ABSTRACT Diabetes mellitus (DM) causes an increased production of free radicals that can impair bone healing. Melatonin is a hormone secreted mainly by the pineal gland, which participates in the neutralization process of free radicals. Objective The aim of this study was to investigate histologic and biochemical effects of supplemental melatonin administration on bone healing and antioxidant defense mechanism in diabetic rats. Material and Methods Eighty-six Sprague-Dawley male rats were used in this study. Diabetes mellitus was induced by intraperitoneal (i.p.) administration of 65 mg/kg streptozotocin (STZ). Surgical bone defects were prepared in the tibia of each animal. Diabetic animals and those in control groups were treated either with daily melatonin (250 μg/animal/day/i.p.) diluted in ethanol, only ethanol, or sterile saline solution. Rats were humanely killed at the 10th and 30th postoperative days. Plasma levels of Advanced Oxidation Protein Products (AOPP), Malondialdehyde (MDA), and Superoxide Dismutase (SOD) were measured. The number of osteoblasts, blood vessels and the area of new mineralized tissue formation were calculated in histologic sections. Results At the 10th day, DM+MEL (rats receiving both STZ and melatonin) group had significantly higher number of osteoblasts and blood vessels as well as larger new mineralized tissue surfaces (p<0.05 for each) when compared with DM group. At the 30th day, DM group treated with melatonin had significantly lower levels of AOPP and MDA than those of DM group (p<0.05). Conclusion Melatonin administration in STZ induced diabetic rats reduced oxidative stress related biomarkers and showed beneficial effects on bone healing at short term.